Manufacturing process for 3D nano-engineered composite materials with aligned carbon nanotubes grown in situ

3D nano-engineered carbon nanotube (CNT) composite plates were manufactured for the first time by a vacuum-assisted resin infusion process. Such processing expands significantly upon the work already developed using hand-layup to a more scalable and relevant processing technology. Alumina-fiber woven fabric with aligned CNTs grown in situ served as reinforcement. Aligned CNTs were grown on the surface of alumina fibers by chemical vapor deposition (CVD), creating a nanoscale, "fuzzy fiber (FF)" hierarchical architecture. FF woven fabric and plain alumina woven fabric plates were fabricated using an unmodified aerospace-grade resin-transfermolding epoxy using vacuum-assisted resin infusion. Optical and scanning electron microscope (SEM) images indicate that composites with and without CNTs were completely impregnated by the resin to the same extent, with less than 1% void fraction in first attempts, and CNTs remained on the surface of alumina fibers after the infusion process. Electrical and mechanical testing of these FF infusion-processed laminates is in progress, and preliminary electrical impedance data is presented herein. This process should greatly simplify the development of new composite materials with significantly enhanced multifunctional properties as has been demonstrated previously for the same architecture processed via hand lay-up. Further refinement of the process parameters is expected to yield lower void-fraction materials as has been demonstrated during refinement of the hand lay-up process for fuzzy fiber reinforced plastics (FFRPs).